Drive mechanism for automatic lathes



INVENTORS. WILLIAM F. GROENE 5 Sheets-Sheet l HARM C.KEMFER D. D mi W F GROENE El AL DRIVE MECHANISM FOR AUTOMATIC LATHES June 21, 1949.

Original Filed Feb. 10, 1943 AITORNEXS W. F. GROENE ETAL DRIVE IECXIANISM FOR AUTOIATIC LATHES Original Filed Fob. 10, 1943 June 21, 1949.-

5 Shoets-Sheet 2 INVENTORS.

n WILUAM F GROENE HARRY c. KEHPER i f ATTORNEYS June 21, 1949. w. F. GROENE ET AL 2,474,104

DRIVE MECHANISM FOR AUTQMATIC LATHES Original Filed Feb. 10, 1943 5 Shets-Sheet 3 wmum EGROEHE HARRY c. KEMPER ATTORNEY! June 21, 1949. w. F. GROENE mm.

DRIVE IECHANISH FOR AUTOMATIC LATHES Original Filed Feb. 10, 1943 5 Shuts-Sheet 4 INVENTORS- wuum F. amen:

HARRY c.\ enrek of g in ATTORNEYS June 21, 1949. w, GROENE ETAL 7 2,474,104

DRIVE MECHANISM FOR AUTOMATIC LATHES Original Filed Feb. 10, 1943 5 Sheets-Sheet 5- MLLIAM EGROENE BY HARRY CLKEMPER Fm im m ATTORNEYE Patented June 21, 1949 2,414,104 muv'n MECHANISM FOR scram-no LATHES William F. Groene, Cincinnati, and Barry C. Kemper, Goshen Township, Clermont County, Ohio, assignors to The R. K. Le Blond Machine Tool Company, Cincinnati, Ohio, a corporation of Delaware Original application February 10, 1943, Serial No. 475,342. Divided and this application August 23, 1944, Serial No. 550,776

1 This invention relates more particularly to the headstock of an automatic lathe incorporating a variable-speed gear drive transmission to the work spindle and a direct belt drive to the spindles to provide a wide range of speeds and, in addition, a smooth, vibrationless drive at high speed through the belt drive transmission to the lathe spindle. These drives are afforded in an integral headstock casing having a dividing partition providing two compartments, namely, a first lubricant-filled compartment for the ear drive transmission, and a second, dry compartment for the belt drive transmission. The entire headstock is an integral unit providing easy access whereby belts may be removed from the spindle and drive pulley without removing the work spindle from the headstock. At the same time, we provide a work spindle amply supported by bearings on each side of the driving pulley.

It is an object of our invention therefore, to provide in an integral unitary headstock for automatic lathes, alternate belt and gear drives from a common power source to a work spindle.

It is a further object to mount said alternate drives in separate compartments of the headstock whereby the gear drive may operate in a body of lubricant while the belt drive is kept dry.

Another object is to provide means whereby the work spindle belts may be removed and replaced easily while at the same time the work spindle pulley is supported in bearings on each side thereof.

Other objects and advantages of our invention will become apparent as the description proceeds.

Referring now to the drawing wherein like numerals are used to designate corresponding parts throughout the several views:

Figure I is an end elevation of an automatic lathe with our headstock incorporated therein, showing the driving motor and the relation of the drive shaft, work spindle, and other essential parts.

Figure II is a front elevation of the headstock, partly in section on line 11-11, Figure IV.

Figure 111 is a section on line III-III, Figures 11 and V, showing the headstock compartment with belt drive. I

Figure IV is a section on the line IV-IV of Figures II and V, showing the gear drive from drive shaft to work spindle.

Figure V is a diagrammatic view substantially along line VV, Figure IV, to show the driving relationship between the several shafts, the change gears for shifting from belt to gear drive,

13 Claims. (Cl. 74-640) and the clutch and brake mechanism between drive shaft and pulley.

Referring in detail to the drawings, the numeral 2 indicates in general the headstock of our lathe having a center 4 on which the workpiece is rotatably mounted at one end. Center 4 is carried by a work spindle 6 which, it will be understood, carries a suitable chucking device or work arbor for driving the work. 'A main driving motor 8 is mounted on a bracket at the back of the lathe, as shown in Figure I, and, through a series of belts 9, drives a clutch and brake pulley Ill, Figure V.

Pully it! incorporates a driving clutch H and brake device i 2. The clutchand brake are operated by a rod l3 slidable in an axial bore of a shaft l6, and shifted axially by a spool I4 having a pin i3a passing therethrough and also passing through an aperture in rod l3 and an axially-extending slot in shaft 16. At its other end rod 13 operates a conventional clutch and brake device of a character, for example, in Patent 1,474,112, dated November 13, 1923.

Below the cover plate 44 is located a shaft IS on anti-friction bearings in the lower compartment and has a gear I! fixed thereto, meshing with a gear I 8, as indicated by the correspondingly numbered dot-and-dash pitch lines on Figure IV. These gears are shown separated in Figure V, it being understood that the latter figure is distorted to bring the axes of the various shafts into the plane of the paper. Gear I8 is fixed to a shaft l9 journaled in bearings supported by one end wall of headstock 2 and an intermediate wall 2a, Figure V. The right-hand end of this shaft, as seen in Figure V, extends in a change gear compartment. formed in the headstock wall and enclosed by a cover plate 20a. Shaft It! has a gear 2| secured thereto within compartment 20. Gear 2| meshes with a'change gear 23. Gear 23 is adapted to be detachably secured, within compartment 20, either to an end of belt drive shaft 22 or an end of shaft 24.

Shaft 22 has a belt pulley 25 fixed to its other end, as seen at Figures 111 and V. Belts 26 connect this pulley with a pulley 21, directly keyed to work spindle 8. These belts also pass over an idler pulley 28, mounted on bearings 29 carried by an eccentric bushing 30. Referring to Figure V, bushing 30 is fixed to an actuating stud 3| having a squared end 32 at the exterior of the housing 2. Thus, by applying a tool to, and turning stud 3|, the pulley 28 may be shifted to tighten the belts. When gear 23 is on shaft 22, power from motor 8 is transmitted to shaft Ii and thence via gears l1, l8, shaft 19, gears 2|, 23,

shaft 22, belt pulley 25, belts 26 and pulley 21 to thus drive headstock work spindle 5;

Shaft 24 has a sleeve 34 keyed thereto. Said sleeve has spaced gears 35 and ,36at its ends as shown at Figure V. A splined shaft 39 is journaled parallel to shaft 24 and has a sliding gear unit thereon consisting of a relatively large gear 31, a smaller gear 38, and an actuating spool.

Gear 31 is of a thickness to fit between without engaging either of gears 35 or 36 and at this time, shafts 24 and 39 are not connected.

The shaft 39 is provided with a spline or any other equivalent or convenient drive connection between the cluster gear 3138 and the shaft 39 for the purpose of making sure that the cluster gear and shaft 39 rotate together on the antifriction bearings carried in the walls 2a and2c of the headstock casing. If the gears 3136 were just mounted on,a cylindrical shaft 39 there would be a tendency for this gear to rotate on the steel shaft resulting in cutting and wear and the lack of use of the anti-friction bearings at the ends of the shaft. Therefore the use of splined shaft is the most economical and sure way of effecting proper axial sliding alignment of the gear 31-38 on the shaft 39 while making sure the shaft rotates in the anti-friction bearing in the headstock casing.

Work spindle 6 has a double gear element keyed thereto consisting of large and small gear elements and 4B. As may be seen from Figure V, the parts are so related that, when gear unit 31, 38 is slid to the left, large gear 31 is moved to mesh with and drivingly connect gears 35 and 40. This connection provides a relatively high speed connection from shaft 16, gears l1, l6, shaft l9, gears 2|, 23, shaft 24, gears 34, 31 and '40, to work spindle 6.

On the other hand, when gear unit 31, 38, is slid to the right, gear 31 meshes with gear 36 on shaft 24 while companion gear 38 engages with large gear 41 on work spindle 6. At this time, the drive is by way of shafts l6 to 24 as previously traced, thence to gears 36, 31, 38 and 4| to work spindle 6. This provides a relatively slower speed than the one previously traced. Shifting of gear unit 31, 38 is effected by a shoe 42, Figure IV, pivoted on the end of a. lever 43. This arm is fixed to a shaft 45 iournaled in a sleeve attached to or integral with, the headstock casing 2. The

shaft extends to the exterior of the casing at I locking plate attached to a headstock casing.

Each hole, of course, corresponds to a predetermined position of gear unit 31, 38. that is, to positions in which (1) gear 31 meshes with and connects gears 35 and 40, (2) gear 31 is free from and located between gears 35, 35 and out of mesh with gear 40 and (3), gear 31 engages gear 36 and gear 38 meshes with 4|.

In this way by shifting gear 23 from one to the other'of shafts 22 and 24, the work spindle 6 may be driven by belt transmission for the higher and smoother speeds required; or a gear drive may be used in case a relatively slower speed is needed; and'in the latter case, the most appropriate of two speeds may be selected.

Referring to Figure V, it will be noted that work spindle 6 is journaled on a bearing 48 at its worksupporting end, a bearing 49 mounted in intermediate wall 21: and between the pulley 21 and 4 the gear unit 40, Al. A third bearing 50 supports the spindle upon the other side of pulley 21. This bearing is carried in a demountable case 5| fitting a bore 52 in the outer rear wall 2b of headstock casing 2 and held in place by screws 53 and a lock nut 54 on spindle 6. When it is desired to change or renew belts 26, screws 53 and lock nut 54 are removed. and case 5!, together with hearing 50' are slid off the end of the spindle. The bearing case 5Lis sufficiently large so that, when removed, a circumferential-space is left between the spindle 6 and the bore 52 through which belts 26 may be passed.

It will thus be apparent that when it is desired to remove the belts 26 from the driving pulley be lifted out through the opening 300. provided in the top of the casing 2 by taking off the cover 301). Each of the belts 26 may then be lifted off of the pulley 25 and passed out through the opening in the rear wall 2?) of the headstock casing 2 provided when the rear spindle bearing case 5| is removed. The work spindle 6 under these conditions remains in perfect operative alignment and in operative position on the bearings 48 and 49 carried in the walls 20 and 20. even though the bearing 50 has been removed from the rear portion of the work spindle.

Thus it can be seen that the headstock is provided with a separating partition 2a, Figure V, which provides a gear drive transmission com-- partment G formed by the front wall 20 in the headstock supporting the bearing 43 of the work spindle 6 and the intermediate wall 2a supporting the intermediate spindle bearing 49. A belt drive compartment 8 is provided between the intermediate wall 2a and the rearwall 2b of the headstock casing 2. Also, it will be further noted that the work spindle is adapted to be journaled in all three of these walls 2a, 2b, and 20 on the respective bearings *46, 49, and 50 during normal operation so as to give the necessary and proper rigidity to the work spindle while at the same time supporting the spindle on each side of the belt drive pulley 21 on the bearings 49 and 50- to maintain proper spindle alignment at all times when the belts 26 are applied to drive the spindle. The pulley drive shaft 22. however, is journaled only in the front wall 2c and the intermediate wall 20. of the headstock casing to allow the belt 26 to be readily lifted off the end of the pulley and past the shaft 22 and threaded out through the opening provided when the rear spindle bearing case 5| is removed.

Power is taken from the headstock drive shaft IE to operate tool feeding mechanism of the posite gear consisting of a large gear 56, and

spiral gear 51, journaled upon shaft 16. Shaft l3, previously described, carries a gear 58 which, as shown in Figure IV, meshes with and drives large gear 56. Spiral gear 51 drives a mating gear 59 carried on a shaft 60 journaled in casing 2. This shaft 60 extends into a change gear compartment 61 at the. backrof the headstock casing. A change gear 62 is mounted on shaft 60 in this compartment which'gear meshes with a second change gear 63 mounted upon a shaft 64, as seen in Figure IV. By this arrangement. shaft 64 may be driven at a plurality of different relatively slow or feeding speeds by changing gears 62 and 68.

A spiral gear 65 is journaled on shaft 64 and meshes with spiral gear 55 so as to effect rapid traverse motion.

In order to selectively take of! feeding motion from shaft 64, or rapid traverse motion from spiral gear 65, the arrangement shown in Figure IV is provided, comprising a clutch member 66 fixed to shaft 64 by pins 61 and having clutch teeth 68 which are adapted to engage mating teeth 68 of an output gear I8. This output gear I8 is journaled on shaft 64 and has a second set of clutch teeth II arranged to engage corresponding teeth I2 on gear 65.

Output gear 18 is axially shiftable on shaft 64 whereby one set of clutch teeth 68 may be engaged with 68 to thereby connect it to shaft 64, or the other set II engaged with teeth I2 on gear 65 to thereby couple said gear directly to spiral gear 65. Thus when output gear 18 is in its left hand position with reference to Figure IV, it is driven at a relatively rapid rate for traverse, while when it is in its right hand position, it is driven at relatively slower feeding speed.

A stud I3 is fixed in casing 2 and a gear I4 is journaled thereon, meshing with output gear 18. The latter is elongated so that the two gears mesh at all times despite axial shifting of gear I8 as described. A worm shaft I5 (Figure II) is journaled at the lower portion of the headstock casing and carries a worm 16 at its central part and a splined pinion 11 adjacent gear 14. Pinion I1 is thus slidably but non-rotatably mounted relatively to shaft 15, the parts being so dimensioned and positioned, that said pinion may be connected to, or disconnected from meshing relation with gear I4.

Sliding of pinion TI is effected by means of a control rod 18, Figure IV, projecting through the front of the lathe base and provided with an operating knob I8.

Worm- 16 meshes with and drives a worm wheel 88 fixed on cam drum shaft 8|. The latter shaft is journaled in bearings 82 and 83 (Figure II) carried in the base of the machine. Worm shaft 15 carries a clutch element 84 at its end projecting at the front of the machine and adapted to be engaged by a crank handle so that shaft 15 may be rotated manually for effecting correct positioning of the work and tools prior to the start of the automatic machining cycle.

Cam drums 85 and 86 are mounted upon shaft 8|. These drums are formed with slots 81 and 88, respectively, for actuating the various tool slides in the manner and for the purpose described in our application Serial No. 475,342, filed February 10, 1943, now Patent No. 2,410,026 dated October 29, 1946, of which the present case is a division.

Control mechanism The various controls and adjustments of the machine are effected by parts whose operation will now be described. Referring particularly to Figures H, IV, and V, the control of driving clutch I I on the input drive shaft I6 is accompllshed by means of the lever 46. A sleeve-88 is mounted in the headstock on shaft 45 and lever 46 is fixed to this sleeve. At its end within the casing, the sleeve has a lever 88 pinned thereto. As shown in Figure 11, a link 8I is pivoted at one end to the lower end of lever 88 and [at its other end to another lever 82 best shownat Figure IlI. Lever 82 is mounted on a suitable pivot in the headstock and has a yoke portion 83 carrying a shoe 84 fitting the annular channel of clutch-actuating spool I4. The connections are such that when lever 46 is in position a, Figure II, the clutch II is open and the brake surfaces are in contact, while, when said lever is moved to position b, the clutch is closed and the brake released. I

This operating lever and clutch II may be automatically tripped to stop the spindle 6 at a predetermined point in the work cycle by mechanism shown more particularly at Figure III. Lever 82 has a cut-away portion forming an opening, as shown at 85. A lever 86 fits within this opening. Levers 82 and 86 are pivoted upon the same pin bearing.

Lever 86 has an upwardly-projecting lug 81 a surface 88 of which is adapted to engage a surface 88 of lever 82, as seen in Figure II. Thus, as seen in said figure, lever 86 is free to rotate counterclockwise without interference from lever 82. However, when lever 46 is in position b, Figure II and the clutch II is closed, rotation of lever 86 in a clockwise direction also engages and correspondingly rotates lever 82. I'his moves hand lever 46 to position a and shifts spool I4 to open clutch II and apply brake I2.

A pin I88 at the lower end of lever 86 pivotallyconnects this lever to a rod I8I threaded at its free end to receive a nut I82. The rod I8I passes through an opening in the headstock casing wall. A spring I83 is mounted on the rod IN and is compressed between nut I82 and the adjacent headstock wall, as seen in Figure II. The spring therefore acts to urge lever 86 in a clockwise direction of rotation.

Referring now to Figure III, a latch I84 is fixed to the lower end of lever 86 at one side thereof. A rock shaft I85 is journaled in the headstock wall on an axis normal to the pivot axis of lever 86 and has a lever I81 fixed thereto. Lever I81 carries at its free end a latch I86,'so positioned as to normally engage latch I84 on lever 86 and thus hold lever 46 in position b, Figure II, wherein, it will be remembered, clutch II is closed. Rock shaft I85 has an arm I88 and roller II8, fixed thereon in position to be rocked by an actuating or trip arm III mounted on-cam drum shaft 8 I. Said arm is adapted to be fixed to shaft 8| by a clamping screw 2.

As the machine is operated in an automatic cycle, shaft 8| is rotated and, at a predetermined point, arm III engages roller II8, rocks arm I88 and shaft I85 and thus moves latch I86 outof engagement with latch I84. Asa result, lever 86 is freed and rocked by spring I83 so that lever 46 is shifted to position a, FigureII, clutch II is opened and the work brought to a rapid stop by brake I2. It will be noted that, as a result of the impositive connection between levers 82 and 86 by way of lug 8I, lever 46 can be operated manually at any time to stop the machine in event of an accident or'any incorrect operation thereof.

Feed and rapid traverse movements may be alternately applied to the cutting tool at a preto rock shaft I I5. At its other end, shaft I I5 has a downwardly-projecting arm II6 with a pin III. Another rock shaft II8 (Figure IV), is journaled in headstock casing 2 and, as shown at Figure II, proceeds to the left to a position adjacent trip arms I26, I21. A forked lever H9 is fixed to this shaft. Each arm of the fork carries an adjusting screw I28 or I2I whose free ends provide a space receiving pin I I1 between them. At its other end,

rock shaft H8 has fixed to it a pair of levers I22, I23 each carrying a roller I24 or I25. As shown at Figure II, these levers I22 and I23 are in different planes normal to their supporting shaft H8 and are so arranged that, when roller I26 of lever I22 is engaged by its trip arm I26, shaft I I8 is rocked clockwise as viewed in Figure III, while, when roller I25 of lever I23 is engaged by its trip arm I2'I, said shaft is rocked in a counterclockwise direction. Arm I26 is clamped to cam drum shaft 8| by a screw I28 while arm I21 is clamped to the same shaft by a screw I29; and it will be understood that all trip arms III, I26 and I21 may be adjusted relatively to, and rigidly secured, in any desired circumferential position about their common shaft 8|.

Thus as shaft 8| rotates, arm I26 will strike roller I24 at a desired point in the operation of our machine, to rock shaft II8 clockwise in Figure III, and, through lever II9, arm II6, shaft H and yoke II4, cause engagement between clutch teeth 1| and I2 to thus cause rapid traverse motion of shaft 8| and its cam drums 85 and 86. On the other hand, when arm I21 engages its roller I25, it moves lever I23 to rock shaft II8 counterclockwise and, through connections previously traced, shift output gear I8 to engage clutch teeth 68, 69 and thus effect a feeding motion of the shaft 8| and its cam drums 85 and 86.

It is desirable to effect transition from traverse to feeding motion and vice versa with a snap action so that shaft 8| shallbe in motion at all times. For this purpose, our invention includes mechanism for rapidly shifting output gear I8 from one position to another. This mechanism includes a loose fit between shoe H3 and its accommodating groove in gear I8, as best'seen at Figure IV. An arm I38 having a pin I3I at its end, is fixed on shaft II5 so as to rock therewith. A detent lever I38 having a detent point I38 is pivoted on shaft I I8 and is'normally urged into a position against pin I3I by means of a tension spring I48 attached to lever I38 at one end and to a pin I4| on the headstock casing at.

its other end.

Said detent lever I38 is shaped, as shown at Figure IV, so that, as shaft H5 is rocked to cause disengagement between the teeth of gear I8 and their mating sets of teeth on gear 65 or member 66, lost motion between shoe 3 and groove II2 permits pin I3I to ride a little beyond the point I39 in the direction it is moving. Thus, just as shoe II3 begins to engage the other side of groove II2, pin I3I begins to slide down one of the surfaces I42 or I43 in a snap action that immediately shifts output gear I8 to its other position. By this mechanism, shift of gear I8 is instantaneous and cam drums 85 and 86 together with trip arms I I I, I26 and I2! are con-. tinuously kept in motion. Screws I28 and I2I are intended primarily to adjust and secure accurate positioning of the levers I 22, I23 with respect to the gear 18 so as to provide the proper action of these members during the automatic operating cycle of the machine.

8 Operation The operation of our invention will now be clear. Prior to starting the machine, the change gear 23 is positioned either upon shaft 22 if a high speed drive is desired, or upon shaft 24 if slower speeds are called for by the work to be operated upon. The arms III, I26 and I2'I are adjusted and secured eircumferentially of their shaft 8|. Arm III is adjusted to stop the machine at the desired point of the cutting tool along the work. Arms I26 and I2! are adjusted to the desired points of the tool relatively to the work at which a change from rapid to feeding traverse of the tool is desired, lever 41 is shifted to move gear element 31, 38 for the selected speed in event the gear drive is to be used instead of the belt drive. A workpiece is loaded into the lathe, the tool brought to position by manual cranking of shaft 15 if necessary, and the driving motor is started. Hand lever 46 is next thrown to position b, Figure 11, to close clutch II and start rotation of the work. The shaft 8| and its drums 85 and 86 are now driven to properly feed the tool relatively to the work. At the proper times, as preselected, arms I26 and I2! engage their respective rollers I24 and I25, to rock forked lever IIS and effect rapid axial movement of gear I8 along shaft 84, as already explained, to shift from feeding to rapid traverse speeds. As the work is completed, actuating arm III engages and trips lever I81 thus releasing lever 96 and permitting spring I83 to act to open clutch II, disconnect pulley I8 from drive shaft I8 and brin the work to a quick stop through the engagement of brake I2.

It will thus be seen that we have provided an automatic lathe with a very wide range of possible operations ranging from high speeds with belt drive, to heavy, slow-speed cutting. Where a surface, not necessary to be worked, is located between two surfaces to be finished, arms I26, I21 are effective to shift gear 18 to rapidly traverse the surface not to be worked, whereafter the gear is again shifted to resume the selected cutting Speed. While the lathe is automatically and positively stopped at the completion of the workpiece, it may, nevertheless, be stopped instantaneously at any point merely by shifting lever 46 to its a position. In addition to the foregoing features, we have provided a lathe which is easily and quickly accessible for adjustment and, at the same time rugged, powerful and capable of the rapid production of work of unsurpassed. accuracy.

Having thus described our invention, what we claim as new, and desire to secure by Letters Patent is:

1. In a headstock for lathes, a two compartment casing, a drive shaft journaled in said casing, a work spindle in said casing, a belt drive in one compartment of said casing connecting said shaft and spindle and including a pulley on said spindle, a gear drive in the other compartment connecting said shaft and spindle hearings in said casing journaling said spindle on both sides of said pulley, and a demountable means carrying one of said hearings in the casing so as to provide a space around said spindle through which belts on said pulley may be removed and replaced when said means is demounted.

2. In a headstock for lathes, a casing, end walls and an intermediate wall in said casing forming a pair of compartments therein, a gear drive transmission in one of said compartments, a belt drive transmission including a belt in the other of said compartments, means for applying power to drive said transmissions, a work spindle journaled in each of said walls, a pulley on said spindle in said belt drive compartment, a demountable rear bearing for said spindle removable to allow insertion or removal of said belt from said belt drive transmission out of said belt drive compartment.

3. In a headstock for lathes, a casing having three wall members forming a pair of compartments therein, a belt drive shaft journaled in two of said wall members, a work spindle Journaled in all three of said wall members, a belt drive transmission including a belt interconnecting said belt drive shaft to said spindle in one of said compartments, a gear drive transmission connected to said spindle in the other of said compartments, means for applying driving power to said belt drive shaft or to said gear drive transmission, and a demountable means carrying one of the journals for said spindle in said walls so as to provide a space around said spindle through which said belt may be removed from or replaced in said compartment containing the belt drive transmission.

4. In a headstock for lathes, having a casing containing outside walls and an intermediate wall forming a pair of compartments therein, a drive shaft journaled in said intermediate and an outside wall of said casing, a work spindle journaled in said intermediate wall and the outside walls of said casing, a gear drive transmission connected to said work spindle located in one of said compartments, a belt drive transmission including a belt between said drive shaft and said spindle located in the other of said compartments, drive means for said transmissions, a demountable bearing means for said spindle in one of the outside walls of said casing forming the belt drive compartment removable to facilitate insertion and removal of said belt from said belt drive transmission without affecting journaled alignment of said work spindle in said casing.

5. In a headstock for lathes, a casing having and walls and an intermediate wall, a drive shaft journaled in an outside and an intermediate wall, a work spindle journaled in all three of said walls, a gear transmission located between said first mentioned outside and intermediate walls operatively connected to said work spindle, a belt drive transmission including a belt located between said intermediate wall and the other outside wall interconnecting said drive shaft and said work spindle, drive means connectable to said gear transmission and said drive shaft, means for removing the outside bearing for said spindle to facilitate installation or removal of said belt from said belt drive transmission.

6. In a headstock for lathes, a casing comprising a pair of end walls and an intermediate wall forming two isolated compartments in said casing, a work spindle journaled in each of said walls, a drive shaft journaled in two of said walls, a gear drive transmission located between said last mentioned two walls, a belt drive transmission between said drive shaft and said work spindlelocated between said intermediate wall and the other wall of said casing, means for demountable journaling said spindle bearing in said other wall so that it may be removed to facilitate insertion or removal of the belt of said belt drive transmission without affectin the position of said work spindle journaled in working position in said other two walls.

7. In a headstock for lathes, a casing having a front wall, a rear wall, and an intermediate wall formed integraltherewith providing a-' pair of isolated compartments therein, a work spindle Journaled in all three of said walls, a demountable bearing for said spindle in said rear wall, a drive shaft journaled in said front and intermediate walls, a gear drive transmission connected to said work spindle and located between said front and intermediate walls, a belt drive transmission interconnecting said drive shaft and said work spindle located between said intermediate wall and said rear wall, and means for applying power to drive said transmissions.

8. In a headstock for lathes having a casing, means in said casing forming a gear drive transmission compartment and a belt drive transmission compartment, a drive shaft journaled in said casing and extending across said gear drive compartment and projecting partially into said belt drive compartment, a work spindle journaled in said casing extending across both of said compartments, a gear transmission connected to said work spindle and located in said gear drive compartment, a belt drive interconnecting the projecting portion of said drive shaft with said work spindle, and removable bearing means for said work spindle associated with said belt drive compartment to allow the belt of said belt drive to be inserted in or removed from driving position between said drive shaft and said, work spindle through an opening formed by the removal of said bearing from said work spindle.

9. In a headstock for lathes, a casing, means in said casing forming a pair of isolated compartments therein, a work spindle journaled in said casing and extending through both of said compartments, a drive shaft journaled in said casing extending through one of said compartments and projecting into the other of said com:- partments, a pulley on said spindle in said othercompartment, a pulley on said drive shaft in said other compartment, belted driving means interconnecting said drive shaft and said pulley on said work spindle, and a gear drive transmission in said first mentioned compartment connected to said spindle, and an idler pulley in said other compartment for maintaining tension in said belt, and mounting means to allow removal of said idler pulley from said other compartment, and demountable bearing support means for said work spindle, removable to permit installation or removal of said belt from said other compartment without affecting the position of said spindle in journaled working position in said casing.

10. In a. headstock for lathes, a casing, having a gear drive compartment and a belt drive compartment, a work spindle journaled to extend through both of said compartments, a gear drive transmission connectable to said work spindle in one of said compartments, a belt drive transmission including a belt connected to drive said spindle in the belt drive compartment, and removable bearing means for said work spindle associated with said belt drive compartment adapted to provide an access opening for inserting or removing said belt without afiecting the position of said spindle in journaled ,working position with said gear drive transmission in said casing.

11. In a headstock for lathes, a casing, having a gear drive compartment and a belt drive compartment isolated therefrom, a work spindle journaled to extend through both of said compartments, a gear drive transmission connectable to l1 said work spindle in one of said compartments, a belt drive transmission including a belt connected to drive said spindle in the belt drive compartment, removable bearing means for said work spindle associated with said belt drive compartment adaptedto provide an access opening for inserting or removing said belt without aflecting the position of said spindle in journaled working position in said casing, belt tightening idler pulley means in said belt drive compartment for maintaining tension on said belt, and means for removing said idler pulley from said compartment to facilitate insertion or removal of said belt through said opening provided by the removal of said removable bearing means.

12. In a headstock for lathes having a three bearing work spindle mounting, a pair of isolated compartments in said headstock each side of said intermediate bearing mounting for said work spindle, a gear drive to said work spindle in one of said compartments, a belt drive to said work spindle in said other compartment including a pulley fixed on said spindle between said intermediate bearing mounting and the rear bearing mounting of said work spindle, and demountable support means for said rear bearing mounting adapted for removal of said rear bearing mounting while said spindle is maintained in aligned working position on the remaining two bearing mountings to facilitate insertion or removal of the belt in said headstock for said belt drive transmission.

13. In a headstock for lathes having a work spindle mounted on three bearings, a belt drive transmission including a belt connected to said spindle by a pulley fixed on said spindle and losaid spindle between said intermediate bearingand the front bearing of said spindle, and common drive means alternately adapted to drive said belt drive transmission or said gear drive transmission to rotate said work spindle.

F. GROEN'E. HARRY C. KEMPER.

REFERENCES CITED The following references are of record in the file of this patent:

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